2007/10/13, Joel B. Mohler <[EMAIL PROTECTED]>:
>
> Thanks for the discussion about this topic. I send this mail to re-iterate
> and summarize. It seems there are two things that you might want:
> 1) Get the coefficient of a specific monomial in the multivariate polynomial
> ring.
> 2) Get the coefficient of the polynomial in a tower of (two) polynomial
> extensions
>
> I suggest that MPolynomial.coefficient method perform function #1 above. It
> currently does some strange things over the base rings I've tested. It does
> vary on base ring due to implementation differences.
>
> I suggest that there be a new method which performs function #2 and I suggest
> it be called "polynomial_coefficient", but I really don't like that name. I
> almost prefer "coefficient_polynomial" since it will sort beside coefficient
> in documentation and help people realize that if they are not happy
> with "coefficient" that they have an alternative. Of course, each method's
> documentation should probably mention the other.
+1,
Those should be 2 separate methods, as they try to solve 2 (slightly)
different problems.
>
> I'm wondering if we could have a vote on preferred syntax. I'm not going to
> describe the parameters because if they are not clear enough from context, it
> probably isn't a good parameter choice :) :
>
> sage: P.<v,w,x,y,z>=ZZ[]
> sage: f=(1-v)*(1-2*w)*(1-3*x); f
> -6*v*w*x + 2*v*w + 3*v*x + 6*w*x - v - 2*w - 3*x + 1
> ##############
> # Alternative Number 1
> ##############
> sage: f.polynomial_coefficient({w:0,v:1})
> 3*x - 1
+1 for this notation.
didier
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